Shower Panel Install Gone Wrong

I had a local plumber that was highly reviewed on Home advisor come out yesterday to install my new shower panel. His plan included cutting out the drywall directly behind the shower to put in a access panel. Unfortunately, the wall behind the shower was at a diagonal angle and he couldn't get the needed access.

Therefore, he needed to make the cutout of the shower valve bigger to access the required plumbing.

The dilemma and the reason for my post:

He didn't cover the hole where the previous shower valve was (see picture below). Moreover, this shower panel has a curved top without a cover, so water can get behind it and my fear that eventually moisture will get in the sheet rock. When he was done with the install, I asked him how he closed the hole in the tile and his answer was "you can buy some insulated waterproof foam and spray it in there." He left it up to me to seal the hole.

Additionally, to seal the shower head, he put on the small delta valve from the prior shower head (see picture) and used silicone to seal the small shower head hole.

However, the large shower valve hole is still unsealed. My question is as follows: Do I use a product like DAP Kwik Foam or is there other alternative solutions to seal the hole? I am concerned of future moisture, water or mold issues if the hole is left unsealed. I am uploading pictures to show the full scope of what I am writing about. Any comments or suggestions will be welcomed as I am not sure what to do in this matter. Furthermore, I am scared to contact another plumber after my experience with a highly rated/reviewed plumber.

In hindsight, I should have not let him off the hook by allowing him to put the burden on me since i hired him to complete the work. Lesson learned.

Previous Shower head and valve: Delta Shower head and valve
New Shower Panel: Pulse Santa Cruz

The last time I installed one of these, I came out with brass nipples through the tile that I was able to seal around. But then the homeowner had the entire shower tiled so it wasn't up to me either.
It did make for a nice clean job.
I may have installed 90's after it left the tile and pointed them down for the flex connectors. There's room behind the panel for the flex connectors to hang.

It seems to me, that there is the possiblity of using something like clear polyseamseal where the stainless unit meets the wall on the sides.
I would not seal the bottom of the unit. If water gets in there, you need an exit for it.
There is a hanger attached to the wall that the shower panel hangs to. It's very easy to lift it off if needed.

FYI
Most plumbers don't do tile. And most tile setters don't do plumbing.
There are a few that I work with, and I love following them on their jobs. I get to do my thing, and they get to do theirs.

Thanks for the replies. That's exactly the info I needed. I have contacted multiple tile contractors to see if they can seal the openings. Now, I have to see if the builder left extra tiles in the attic. Hopefully, I can have the tile work done soon so the wife can use the shower again.

I contacted the shower panel manufacturer and they told me that there should be stub-outs that protrude out of the tile by an inch or so just in case there are future leaks.

After I have the tile guys come out and take a look to see if they can do the job, I will have a plumber come out and install the required stub outs (per the instruction manual I gave the plumber who installed the panel) and then tile around it. I believe the Flex supply lines are part of the shower panel and per manufacturer should never be inside the wall but instead outside connected to stub outs.

My only concern is with the stub-out: how will the shower panel hoses connect to the stub out without making an odd 90 degree turn and not kinking? Terry, reading your thoughts on this, installing 90's should provide the needed space for the hoses?